Distal wire securement in steerable catheter

ABSTRACT

A secure attachment method and structure for a wire (including non-metallic fiber, yarn, cable, etc.) is provided within a steerable catheter that includes a proximal end, a distal end, and an intermediate catheter body length therebetween, with at least a first catheter lumen extending longitudinally through the catheter body, at least a first elongate wire disposed longitudinally through the first catheter lumen, and a first adhesive having a first viscosity, the first adhesive disposed substantially within, and securing the wire to, the first longitudinal catheter lumen, where at least a lengthwise portion of the wire is frayed or otherwise at least partially disaggregated. The structure and method provides for robustly secure affixation that will allow steering/deflection control by manipulation of another portion of the wire.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional application which claims priorityto U.S. provisional application Ser. No. 62/367,951; filed Jul. 28,2016, which is incorporated by reference herein in its entirety.

TECHNICAL FIELD

Embodiments disclosed herein generally relate to steerable catheters,including endoscopes. More particularly embodiments disclosed hereinrelate to a structures and methods for securely attaching the controlwires/fibers within a steerable catheter.

BACKGROUND

Deflecting catheters, also referred to as steerable catheters are usedin a variety of medical and non-medical procedures. In diagnostic andtherapeutic medical procedures, a steerable catheter provides anoperator (e.g., physician) with the ability to articulate the distal tipof the catheter in order to travel through constrained and/or tortuousanatomy, and/or to direct the distal catheter tip in a particulardirection. Similar mechanisms are used in medical and nonmedicalendoscopes to steer them to a target site and to orient a device portion(e.g., including a camera or other visualization means) in a desireddirection.

In a typical design, control wires are manipulably attached at aproximal end of the device, and also attached at or near a distal end ofthe device. Such a configuration operates by manipulating one or more ofthe control wires to increase and/or decrease a generally longitudinalforce on the distal device end that will deflect it in a desireddirection. In order to prevent a premature or undesired deflection ofthe device, it is necessary to provide a balanced starting tensionbetween the proximal and distal ends of the control wires. Variousmechanisms in the art have been developed for doing this includingthreaded tensioning bolts or pins that include an aperture transverselythrough a head and/or shaft for receiving a proximal end portion of oneor more control wires, which can then be tightened or loosened in orderto provide a desired tensioning level of the control wire(s). Thesemechanisms often are mounted to a shaft or housing of the steerabledevice.

It is be desirable to provide tensioning means that provide finelytunable tensioning for very small diameter fibers, where thetuned/tensioned fibers will be secure in order to provide predictableand desirable steering behavior for a steerable catheter, andparticularly for a steerable cholangioscope or other small-diameterendoscope, including providing highly-secure proximal-end anchoring ofthe fibers to/within the control handle.

BRIEF SUMMARY

In one aspect, embodiments disclosed herein may include a steerablecatheter device with steering control wires fixedly attached in a distalend of a catheter shaft, as well as methods for effecting that fixedattachment.

In one aspect, embodiments disclosed herein may include a secureattachment of a wire within a steerable catheter that includes aproximal end, a distal end, and an intermediate catheter body lengththerebetween, with at least a first catheter lumen extendinglongitudinally through the catheter body, at least a first elongate wiredisposed longitudinally through the first catheter lumen, and a firstadhesive having a first viscosity, the first adhesive disposedsubstantially within, and securing the wire to, the first longitudinallumen, where at least a lengthwise portion of the wire is frayed orotherwise at least partially disaggregated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a steerable catheter device embodiment;

FIG. 2 is a partially disassembled perspective view of the embodiment ofFIG. 1;

FIG. 3 shows inner and outer spools with two exemplary (of four total)control-wire winding gears;

FIGS. 4A-4B depict the spools assembled together with control wires andcontrol wire tubes;

FIGS. 5A and 5B show a face of the inner spool, respectively, withoutand with a pair of engaged control-wire winding gears;

FIG. 6A shows an outer face of the outer spool, assembled to the innerspool (of which portions, including inner spool gears, are partiallyvisible;

FIG. 6B shows an inner face of the outer spool;

FIGS. 7A-7D show four different views of a control-wire winding gear;

FIGS. 7E-7F show opposed sides of the control-wire winding gear, forillustration of engaging with a control wire;

FIG. 8 is a transverse section view taken along line 8-8 of FIG. 1,showing an eight-lumen catheter body; and

FIGS. 9-9D are longitudinal section views of the distal catheter body,taken along line 9-9 of FIG. 8, with FIGS. 9A-9D showing one(non-limiting) method of securely and permanently affixing a controlwire within a distal end of the catheter.

DETAILED DESCRIPTION

Various embodiments are described below with reference to the drawingsin which like elements generally are referred to by like numerals. Therelationship and functioning of the various elements of the embodimentsmay better be understood by reference to the following detaileddescription. However, embodiments are not limited to those illustratedin the drawings. It should be understood that the drawings are notnecessarily to scale, and in certain instances details may have beenomitted that are not necessary for an understanding of embodimentsdisclosed herein, such as—for example—conventional fabrication andassembly.

Generally, embodiments disclosed herein relate to a structure and systemfor securely attaching the proximal ends of control wires (including anykind of control fiber, regardless of construction material) to thecontrol spool(s) of a steerable catheter. In the most preferredembodiments, the structure and system include means for tuning—that isfinely adjusting—relative tension of each of those control wires betweenthe proximal end and a permanently/securely attached distal control wireend attached more distally within the steerable device. Too much or toolittle tension in each of the control wires (on its own, and moreparticularly in relation to the other control wire(s)) can causepremature or otherwise undesired deflection of the steerable deviceand/or may cause the steerable device to operate in a manner that is notdesired or predictable. During assembly of a steerable catheter device,the system can be used to take up slackness one or all control wires.

The invention is defined by the claims, may be embodied in manydifferent forms, and should not be construed as limited to theembodiments set forth herein; rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey enabling disclosure to those skilled in the art. As used in thisspecification and the claims, the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.

The terms “proximal” and “distal” are used herein in the common usagesense where they refer respectively to a handle/doctor-end of a deviceor related object and a tool/patient-end of a device or related object.The term “about,” “substantially,” and other relative terms and terms ofdegree, when used with reference to any volume, dimension, proportion,or other quantitative value is intended to communicate a definite andidentifiable value within the standard parameters that would beunderstood by one of skill in the art, and should be interpreted toinclude at least any legal equivalents, minor butfunctionally-insignificant variants, and encompassing a range thatincludes up to a range mathematically significant figures, although notrequiring the full breadth of such range.

The term “control wire” (including just “wire”) is used herein to denotethe elongate members that connect a control surface of a steerablecatheter with a deflectable distal portion of the catheter, and it mayinclude metallic, polymeric, and/or other materials including—by way ofnon-limiting example—ultrahigh molecular weight polyethylene yarn (e.g.,Dyneema™), aramid fibers, monofilament line, multifilament/multifilarcable, and/or other materials that preferably have high tensile strengthwith low longitudinal stretch so as to provide predictable operationbehavior. With regard to distal attachment of the control wire(s), amultifilar, braided, or other structure is preferred, which may be atleast partially frayed or otherwise partially disaggregated (e.g., inorder to provide greater surface area than a unitary aggregated wirestructure, as described further below). One example of a control wiremay include a 4×-50 Denier ultra-high tenacity polyethylene braid havinga very small outer diameter of about 0.18 mm (measured in accordancewith ASTM D-1907); high strength (about 5.6 kg, and at least equal to orgreater than 4.75 kg, measured in accordance with ASTM D-6775); lowlongitudinal stretch/elongation (about 5%, ±2%, measured in accordancewith ASTM D-6775) (e.g., as available from Textile DevelopmentAssociates Inc. of Brookfield, Conn.). Certain preferred control wireembodiments include or may even consist of high modulus fiber materialthat is nonconductive and/or substantially nonstretching. In oneembodiment, a high modulus fiber control wire material may be braided.One such high modulus fiber material can be a High Molecular DensityPolyethylene, a melt spun liquid crystal polymer fiber rope, or a spunpara-aramid fiber polymer, or a high strength ceramic fiber. In someembodiments, a high modulus fiber control wire material may have atensile strength in a range of about 300 ksi (2,000 MPa) to 1,500 ksi(10,400 MPa), and/or a tensile modulus in the range of about 5,000 ksi(35,000 MPa) to about 20,000 ksi (140,000 MPa).

One embodiment of a steerable catheter device 100 is described withreference to FIG. 1. The steerable catheter device 100 includes aproximal control handle body 102 with a steerable catheter body 104extending distally therefrom. Various embodiments may include one ormore different steering control means known in the art. This illustratedembodiment includes a pair of control wheels, with an outer controlwheel 110 and an inner control wheel 130. As set forth in greater detailbelow, the outer control wheel 110 is disposed in mechanicalcommunication with a pair of control wires that are operable, upon wheelrotation, to deflect the catheter body 104 along a first plane, and theinner control wheel 130 is disposed in mechanical communication withanother pair of control wires that are operable, upon wheel rotation, todeflect the catheter body 104 along a second plane that may be generallyorthogonal to the first plane. Simultaneous or sequential operation ofthe outer and inner wheels 110, 130 preferably can deflect the distalend portion 160 of the catheter body 104 in any direction around a360-degree circle defined generally by a circumference of the catheter.This embodiment also shows a mounting structure 106 that may be used tomount the steerable catheter 100 to another device (e.g., an endoscope,or other piece of equipment). Steering mechanisms using control wiresare well-known in the art including in U.S. Pat. Pub. No. 2015/0366435to Williams, which is incorporated herein by reference in its entirety.The overall control structure described is also well known in thesteerable device art, including particularly the endoscope art, butthose devices lack the currently disclosed finely-controlled mechanismfor efficient and effective tensioning of control wires. Certainembodiments in keeping with the present disclosure may include at leastone visualization element (as well as supporting hardware and/orsoftware, not shown—but well-known in the art and readily understandableas using electrical and/or optical devices such as CCD, fiber optic,CMOS, etc.) for use of such embodiments as endoscopic devices including,for example, as a cholangioscope configured for use with and through alarger endoscope.

A partially disassembled view of the control handle portion of thesteerable catheter device 100 is shown in FIG. 2, and the spoolassemblies therein are shown in more detail in FIG. 3. The outer controlwheel 110 engages a shaft 114 of, and controls rotation of, an outerspool 112. The outer spool 112 includes a circumferential groove 115around its outer circumferential surface, which groove 115 receives atube 117 through which extend the proximal end regions of opposed firstand second control fibers 116, 118. The outer spool 112 includes twogear-mounting apertures 121 a, 121 b, each of which receives and forms arotation-permitting engagement with the split mounting end 152 of a gear150. The inner control wheel 130 engages a shaft 134 of, and controlsrotation of, an inner spool 132. The inner spool 132 includes acircumferential groove 135 around its outer circumferential surface,which groove 135 receives a tube 137 through which extend the proximalend regions of opposed third and fourth control fibers 136, 138. Theproximal end terminus of each control wire (not shown other than byexample in FIG. 7E) is secured to a gear. Those of skill in the art willappreciate that rotary actuation of the outer control wheel 110 effectscorresponding rotary actuation of the outer spool 112, while rotaryactuation of the inner control wheel 130 effects corresponding rotaryactuation of the outer spool 132.

As shown in FIGS. 3 and 4A, the outer spool shaft 114 extends throughand beyond a central passage of the inner spool 132 and its shaft 134.In FIG. 3, only two of four actual gears 150 are expressly shown, but itshould be appreciated that a four-wire control system will include fourgears 150, each securing a proximal end portion of one of those fourwires (e.g., 116, 118, 136, 138). More detailed views of the gears 150are shown in FIGS. 7A-7D. Each of the spools 112, 132 also includesgear-engaging detents, which are depicted here as flexible beams 122 a,122 b, 142 a, 142 b. The outer spool 112 also includes a pair ofgear-adjustment access apertures 124 a, 124 b, which allow access to thegears 150 engaged into the inner spool 132 when the two spools, 112, 132are rotationally oriented and aligned in a predetermined position asshown, e.g., in FIGS. 3 and 4A. With this structural configuration, auser can access each of the gears 150 to turn it and thereby adjust theslackness and/or tension of a control wire attached to the gear. Thisability remains when the spools are assembled together, and when theyare engaged to their respective control wheels 110, 130, provided thatthe spools are aligned in a predetermined manner (required forpost-assembly adjustment of the inner spool 132).

FIGS. 4A-4B show the outer spool 112 rotatably engaged with/through theinner spool 132, where the split mounting end 152 of the gears 150engaged rotatably into the apertures 121 a, 121 b of the outer spool arevisible. The hex-receiving heads 154 of the gears 150 (that arerotatably engaged into the inner spool 132) are visible through thegear-adjustment access apertures 124 a, 124 b. The outer spool tube 117and inner spool tube 137 are shown engaged in their respective grooves115, 135. Control wires 116, 118 extend from the ends of the outer spooltube 117, and control wires 136, 138 extend from the ends of the innerspool tube 137.

As shown in FIGS. 5A-5B and 6A-6B, respectively, the inner spool 132 andthe outer spool 112 each include control wire passages. FIG. 5A showsthe outer spool-facing surface of the inner spool 132, and FIG. 5B showsthe same surface, with gears 150 mounted therein. For the inner spool132, a pair of control wire passages 146 a, 146 b extend from the groove135 into, respectively, the gear receptacles 145 a, 145 b. FIG. 6A showsan outward facing surface of the outer spool 112 (including gearsengaged into the outer spool 112, with a view through its openings ofdetents 142 a, 142 b and of gears engaged into the inner spool 132), andFIG. 6B shows the opposite surface without the gears. For the outerspool 112, a pair of control wire passages 126 a, 126 b extend from thegroove 115 into, respectively, the gear receptacles 125 a, 125 b. Theorientation of each passage is configured to provide a minimal anglerelative both to the groove and to the gear receptacle so that when acontrol wire is directed through the passage and engaged to the gear,there are minimal stress risers that could serve as binding pointsand/or that could introduce undesirable point stresses to the controlwires during device operation. Once assembled to a spool and engagedwith a control wire each of the gears rotates in place without movingalong or out of a central radial/rotary axis.

FIGS. 7A-7D show four views of the control wire tensioning gear 150.Each gear includes a splayed/split mounting end 152 that is used in a“clip-in” engagement into—and allowing rotation within—gear-mountingapertures (121 a, 121 b, 141 a, 141 b). The split mounting end 152 issufficiently flexible and resilient to engage securely but rotatablywithin those gear-mounting apertures. Each gear also includes ahex-receiving head 154, shown here as planar and circular, connectedwith and separated from a gear-toothed disk 158 by a core member, thesurface of which forms a control-wire-receiving circumferential groove156 of the gear 150.

The faces of adjacent gear teeth 158 a preferably are oriented about 90°relative to each other and at about 45° relative to a radially centraldiameter, as shown in the drawings. This construction provides for afirm and secure engagement of the squared off end of a detent betweenadjacent teeth. As shown, for example, in FIG. 6A, the squared-off endof a detent embodied as a flexible beam 122 a is firmly and securelyengaged between adjacent gear teeth. Those of skill in the art willappreciate that a hex-head tool (e.g., Allen wrench) can be engagedwithin the hex-shaped opening of the split mounting end 152 so as torotate the gear. In FIG. 6A, rotation of the lower-right gear in theclockwise direction indicated by surface marking arrow 122 x willdeflect the beam 122 a and allow the gear to rotate in a controlledmanner. With reference to FIG. 6B, it will be appreciated that a controlwire passing from the groove 115 through the passage 126 a into the gearreceptacle 125 a can be secured to a gear therein and will be (with saidrotation) wound up around the gear to gather slack and adjust tension.In the event that the gear is wound farther than desired, the detent 122a can be deflected to allow the gear to be rotated/released in theopposite direction (thereby reducing tension on the control wire).

With reference to FIG. 6A and FIG. 5B, it should also be appreciatedthat the detents 142 a, 142 b and gears of the inner spool 132 can beadjusted when the inner and outer spools are assembled together. Thehexagonal apertures of the gear heads 154 can be engaged forwire-tightening/tensioning rotation in the direction shown by therespective surface indicia arrows (on the upper portion of FIG. 6A).And, if there is a desire of a user to counter-rotate either inner spoolgear, the inner spool detent 142 a, 142 b engaged to the gear can bedeflected by accessing them through the central opening of the outersurface gears between their respective split mounting ends 152.Preferably, each of the control wires 116, 118, 136, 138 is directed amaximal distance around the spool to which it is engaged, which those ofskill in the art will understand to provide a more desirable range ofmechanical movement for/of the control wires with regard to controlleddeflection of the catheter distal end.

The preferred travel path of each control wire is described withreference to FIGS. 4A, 5A, and 6B. On the outer spool, the control wire116 is disposed through the longitudinal central lumen of the tube 117and exits a tube opening (not shown) that is aligned with the controlwire passage 126 a, through which passage 126 a the wire 116 is disposedto engage around a gear rotatably mounted in the gear receptacle 125 a.The control wire 118 (a distal end of which preferably is securelyfixedly attached in a distal catheter portion, about or exactly 180°opposite of control wire 116) is disposed through the longitudinalcentral lumen of the tube 117 and exits a tube opening (not shown) thatis aligned with the control wire passage 126 b, through which passage126 b the wire 118 is disposed to engage around a gear rotatably mountedin the gear receptacle 125 b.

On the inner spool, the control wire 136 is disposed through thelongitudinal central lumen of the tube 137 and exits a tube opening (notshown) that is aligned with the control wire passage 146 a, throughwhich passage 146 a the wire 136 is disposed to engage around a gearrotatably mounted in the gear receptacle 145 a. The control wire 138 (adistal end of which preferably is securely fixedly attached in a distalcatheter portion—not shown, about or exactly 180° opposite of controlwire 136) is disposed through the longitudinal central lumen of the tube137 and exits a tube opening (not shown) that is aligned with thecontrol wire passage 146 b, through which passage 146 b the wire 138 isdisposed to engage around a gear rotatably mounted in the gearreceptacle 145 b.

Each control wire preferably is securely and permanently attached to agear 150 in a manner that provides for predictable and desirableperformance of the device with regard not only to removal of slack andtensioning during assembly of a steerable catheter device, but alsoduring operation of the device including steering/deflection of thedistal catheter portion. In view of the foregoing description, it shouldbe appreciated that, during assembly, a proximal end of the control wireis directed into a gear receptacle via a control wire passage. For thesake of exemplary illustration, reference is made here to FIGS. 6B and7A-7F. When directed through the control wire passage 126 b, a distalend of the control wire 118 (not shown in FIGS. 6B-7D) will traverse thegear receptacle 125 b in a position that will align with the groove 156of a gear 150.

In one preferred embodiment, the control wire will be directed from thegroove 156 through a wire-securing fenestration 155 that is open throughthe gear head 154. From that fenestration 155, the distal end of thewire 118 passes along and within a slot 155 a disposed radially in theoutward face of the gear head 154, then traverses the thickness of thegear head 154 via a notch 155 b (which notch is within the outercircumference of the gear head 154). There, back within the groove 156,the distal end of the wire 118 can be knotted around a less-distalportion of the wire 118, and the knot preferably secured with adhesive(knot not shown, but various knots and adhesives are well-known in theart). It will be appreciated that a couple of turns of the wire aroundthe core within the groove will additionally frictionally secure thewire around the groove, whereupon the split mounting end 152 of the gearcan be mounted/“clicked” into the gear-mounting aperture 121 b foradjustment to take up slack and tension the wire as described above.Those of skill in the art will appreciate this process with respect toproviding secure windability of the control wires relative to each ofthe four gears in the drawings and this description, which four wiresand gears provide for controlled deflection/movement along and betweenall four transverse axes of the distal catheter end. It is preferablethat the control wire be secured around/through the gear head and notthrough the core/shaft—both for ease of assembly, and also to minimizethe stress risers present in the wire along its load-bearing regionsduring tensioning and operation of the steerable catheter.

One of the challenges in constructing a steerable catheter device(including particularly very small-diameter devices, such as a deviceconfigured for use as a cholangioscope) is securely andfixedly/permanently attaching control wires within the distal end, whichis imperative for predictable and consistent steering performance. Withreference to FIG. 1, for such a device, it is preferable that the distalend portion 160, which here includes a distal length to the distalmostend terminus, be controlled finely and accurately by the steeringmechanism so as to be able to be oriented in any direction around a360-degree circle defined generally by a transverse circumference of thecatheter body. FIG. 8 shows a transverse section view of the distal endcatheter body portion 160 (taken along line 8-8 of FIG. 1).

The catheter body distal portion 160 shown includes eight lumens thatextend longitudinally through the catheter body 104, where all of thoselumens are at least generally, preferably substantially, or even exactlyparallel with each other. The first and second control wire lumens 166,168 may receive the paired opposite control wires 116, 118, where thefirst and second lumens are disposed radially 180° opposite each otheracross a radially off-center longitudinal axis of the catheter body. Thethird and fourth control wire lumens 176, 178 may receive the pairedopposite control wires 136, 138, where the third and fourth lumens alsoare disposed radially 180° opposite each other across a radiallyoff-center longitudinal axis of the catheter body. As shown, relative tothe radially off-center longitudinal axis of the catheter body, thefirst and fourth lumens, and the second and third lumens each aredisposed radially less than 90° from each other, respectively. Other,larger lumens shown may be configured for purposes other than allowingpassage of a control wire (e.g., for passage of a wire guide or otheraccessory, illumination structure, visualization elements/structures,introduction/extraction of fluids, and/or other purposes). In oneembodiment, the outer diameter of the distal end portion 160 may beabout 4 mm, with the inner diameter of the control wire lumens 166, 168,176, 178 each being about 0.3 mm, and the inner diameters of the otherlumens ranging from about 0.75 mm to about 1.5 mm.

Within each of the control wire lumens, the respective control wire mostpreferably is free to move longitudinally except for a distalmost lengththat is securely and fixedly attached within a distalmost terminallength of the corresponding control wire lumen. In some embodiments, atleast that a distalmost terminal length of the control wire lumen has aconsistent/constant and uniform inner diameter that does not get largerat or near the distalmost terminus of the catheter body. In otherembodiments, the distalmost terminal length of the control wire lumenmay be slightly but smoothly flared to a larger inner diameter, butwithout any stepped or sharp transition of diameter. This is moreclearly shown in FIG. 9, which is a longitudinal section view of thedistal catheter body portion 160 taken along line 9-9 of FIG. 8,crossing through the radially off-center longitudinal axis.

A non-limiting exemplary method of securing a control wire, useful ineach of the control wire lumens, is described here with reference toFIGS. 9A-9D. The wire and adhesives are not drawn to scale. As shown inFIG. 9A, a control wire 116 is directed through the control wire lumen166, leaving a distalmost end terminal length of the control wireoutside the distal terminus of the catheter distal end portion 160. Alengthwise portion 116 x of the exposed wire is frayed or otherwise atleast partially disaggregated. For an UHMWPE fiber, other (e.g.,non-UHMWPE) polyethylene fiber, or braided or twisted polymer fiber oryarn, this may be done by gripping and pulling with a tool (e.g.,tweezers, pliers, blade edge) along and past the distalmost terminal endof the wire. Control wire comprising another yarn or cable material maybe unwound or otherwise disaggregated into a plurality or othermultiplicity of component fibers—most preferably without breaking,cutting, or weakening the longitudinal composition of those componentfibers.

A pair of side holes 163, 165 is also shown in FIGS. 9A-9D. These holesare configured for introducing flowable adhesive into the lumen 166. Asshown in FIG. 9B, the wire 116 is drawn into the lumen 166—preferably sothat the frayed/disaggregated distal ends are at least generally alignedwith or flush with the distal terminal catheter end. Then, as shown inFIG. 9C a more-viscous adhesive 172 is wicked or otherwise directedthrough the more-proximal hole 163 into the lumen 166 and around thewire 116, where the adhesive generally surrounds and may at leastpartially permeate the wire (particularly for embodiments where thefrayed/disaggregated distal length 116 x extends proximally to or pastthe more-proximal hole 163). The introduction of adhesive, whether bywicking, injection, or other means may include some capillary action aswell, thereby allowing cross-sectional filling of the lumen 166 throughand around the wire 116 and its frayed portion. Most preferably, themore-viscous adhesive 172 does not block the more-distal side hole 165.As shown in FIG. 9D, a less-viscous adhesive 174 is wicked or otherwisedirected through the more-distal hole 165 into the lumen 166 and aroundthe wire, where the adhesive generally surrounds and may at leastpartially permeate the wire and—as thoroughly as possible—permeatesbetween, intersperses, and engages with the frayed or otherwise at leastpartially disaggregated elements of the distalmost terminal wire end 116x. Thereafter, any excess adhesive is cleaned off and the adhesive isallowed to cure and set in a manner that permanently fixes and securesthe wire 116 within the distal length of the lumen 166. More proximally,the wire preferably is at least generally freely movable within thelumen, and its opposite (proximal) end may be secured within a controlhandle as described above, or by other means known or developed in theart.

Those of skill in the art will appreciate that a variety of differentparticular adhesives may be used in view of the presently disclosednovel structures and methods. The particular choice(s) of adhesive(s)may vary in keeping with the materials used for the catheter and thewire(s), as well as with regard to the dimensions and particularapplication/environment for which a given steerable catheter isconfigured. One exemplary embodiment of the present disclosure includesdistalmost end terminal catheter length 160 extruded as a 50/50 blend ofPEBAX-7233 and Nylon-12. With this material, and with a 4×-50 Denierultra-high tenacity polyethylene braid (described above, having itsdistalmost terminal end length 116 x teased out and frayed), one exampleof a proximal-use, more-viscous adhesive may be a cyanoacrylate of about100 cP (e.g., Loctite™ 401), and one example of a distal-use,less-viscous adhesive may be a cyanoacrylate of about 3 cP (e.g.,Loctite™ 4014).

Other effective adhesives may include UV-curable and/or otherlight-curable adhesives. The viscosity of the adhesives may be selectedwith particular reference to the absolute and relative sizes of the wirelumen(s) and the wire(s). The materials and sizes, particularly of thewire(s) will be selected to transfer desired/needed force withoutbreaking or stretching, without binding in the lumen(s), and alsoremaining small enough to keep the overall device of a desired size.Also, the catheter may include one or more metallic and/or polymericreinforcing members (e.g., within the catheter wall, on the catheterwall exterior), but the control wires are not directly attached to anysuch members by the adhesive nor by other engagement. In preferredembodiments, the control wires exclude any sheath member, beingconstructed of materials that provide desired strength and limitedelasticity in the very small diameters contemplated for the deviceembodiments described herein.

Those of skill in the art will appreciate that embodiments not expresslyillustrated herein may be practiced within the scope of the claims,including that features described herein for different embodiments maybe combined with each other and/or with currently-known orfuture-developed technologies while remaining within the scope of theclaims. Although specific terms are employed herein, they are used in ageneric and descriptive sense only and not for purposes of limitationunless specifically defined by context, usage, or other explicitdesignation. It is therefore intended that the foregoing detaileddescription be regarded as illustrative rather than limiting. Referencesherein to any industry standards (e.g., ASTM standards, and productidentifiers such as particular polymers, as well as any trademarks) aredefined as complying with the currently published standards andcorresponding quantitatively and qualitatively defined specifications asof the original filing date of this disclosure unless expresslyotherwise defined herein. And, it should be understood that thefollowing claims, including all equivalents, are intended to define thespirit and scope of this invention. Furthermore, the advantagesdescribed above are not necessarily the only advantages of theinvention, and it is not necessarily expected that all of the describedadvantages will be achieved with every embodiment. In the event of anyinconsistent disclosure or definition from the present applicationconflicting with any document incorporated by reference, the disclosureor definition herein shall be deemed to prevail.

I claim:
 1. A secure attachment of a wire within a steerable cathetercomprising: an elongate catheter body including a proximal end, a distalend, and an intermediate catheter body length therebetween; at least afirst catheter lumen extending longitudinally through the catheter body;at least a first elongate wire disposed longitudinally through the firstcatheter lumen; a first adhesive having a first viscosity, the firstadhesive disposed substantially within, and securing the wire to, thefirst catheter lumen, where at least a lengthwise portion of the wire isfrayed or otherwise at least partially disaggregated.
 2. The secureattachment of claim 1, further comprising a second adhesive disposedsubstantially within, and securing the wire to, the first catheterlumen, where the second adhesive has a second viscosity different thanthe first viscosity.
 3. The secure attachment of claim 1, furthercomprising a first side hole providing fluid communication between theat least a first catheter lumen and an exterior of the catheter body,which first side hole extends through the catheter body.
 4. The secureattachment of claim 3, further comprising a second side hole providingfluid communication between the at least a first catheter lumen and theexterior of the catheter body, which second side hole extends throughthe catheter body in a location distal of the first side hole.
 5. Thesecure attachment of claim 4, where the first adhesive having a firstviscosity is disposed adjacent to, and in contact with, the first sidehole.
 6. The secure attachment of claim 4, where the first adhesivehaving a first viscosity is further disposed proximal of the first sidehole.
 7. The secure attachment of claim 4, further comprising a secondadhesive disposed substantially within, and securing the wire to, the atleast a first catheter lumen, where the second adhesive has a secondviscosity that is less than the first viscosity, and where the firstadhesive is disposed proximal of the second adhesive.
 8. The secureattachment of claim 4, further comprising a second hole through thecatheter body in fluid communication with the at least a first catheterlumen.
 9. The secure attachment of claim 8, further comprising a secondadhesive disposed substantially within, and securing the wire to, the atleast a first catheter lumen, where the second adhesive has a secondviscosity that is less than the first viscosity, and where the firstadhesive is disposed proximal of the second adhesive.
 10. The secureattachment of claim 9, where the second adhesive is disposed at least ina catheter lumen region distal of the second hole.
 11. A method offorming the secure attachment of claim 9, said method comprising stepsof: directing a distal lengthwise portion of the wire into a distal endof the at least a first catheter lumen where a distalmost terminal endof the wire is frayed or otherwise at least partially disaggregated, andwhere said distalmost terminal end is within or immediately adjacent toa distalmost end terminal length of the at least a first catheter lumen;directing the first, more viscous, adhesive through the first hole intothe at least a first catheter lumen in a manner that attaches andsecures the wire within the at least a first catheter lumen, withoutblocking the second hole; directing the second, less viscous, adhesivethrough the second hole in a manner that intersperses with and securelyengages the frayed or otherwise at least partially disaggregateddistalmost portion of the wire within the distalmost end terminal lengthof the at least a first catheter lumen.
 12. The secure attachment ofclaim 9, where the at least a first catheter lumen includes a constantinner lumen diameter along a distalmost end terminal length of the atleast a first lumen within which lumen length is disposed both thesecond adhesive and a distalmost terminal end of the at least alengthwise portion of the wire contacting the second adhesive.
 13. Asteerable catheter comprising: an elongate catheter body including adistal end, with at least a first catheter lumen extendinglongitudinally through, and open to, the distal end; at least a firstelongate wire disposed longitudinally through the at least a firstcatheter lumen; a first adhesive having a first viscosity, the firstadhesive disposed substantially within, and securing the wire to, the atleast a first catheter lumen; and a second adhesive having a secondviscosity different than the first viscosity—disposed substantiallywithin, and securing the wire to, the at least a first catheter lumen,distal of the first adhesive where at least a lengthwise portion of thewire contacting the second adhesive is frayed or otherwise at leastpartially disaggregated.
 14. The steerable catheter of claim 13, furthercomprising at least one visualization element disposed near the distalend of the catheter body.
 15. The steerable catheter of claim 13,further comprising at least a second catheter lumen extendinglongitudinally through, and open to, the distal end, where said secondcatheter lumen is at least generally parallel with the first catheterlumen and is disposed radially 180° opposite the first catheter lumenacross a radially off-center longitudinal axis of the catheter body, andwhere a second elongate wire is disposed longitudinally through, andsecured by at least one adhesive within, the second catheter lumen. 16.The steerable catheter of claim 15, further comprising a third catheterlumen and a fourth catheter lumen, where each of the third catheterlumen and the fourth catheter lumen is at least generally parallel withthe first catheter lumen; where each of the fourth catheter lumen andthe third catheter lumen are disposed radially less than 90° from,respectively, the first catheter lumen and from the second catheterlumen, relative to the radially off-center longitudinal axis of thecatheter body; where a third elongate wire is disposed longitudinallythrough, and secured by at least one adhesive within, the third catheterlumen; and where a fourth elongate wire is disposed longitudinallythrough, and secured by at least one adhesive within, the fourthcatheter lumen.
 17. The steerable catheter of claim 16, where the distalend of the catheter is configured to be deflected in a controlled mannerby simultaneously increasing and decreasing pulling force, respectively,upon the first elongate wire and second elongate wire and/or the thirdelongate wire and fourth elongate wire.
 18. The steerable catheter ofclaim 16, where each of the catheter lumens has a uniform consistentinner diameter along at least a distalmost terminal end length, withinwhich length each of the elongate wires is disposed and secured.
 19. Thesteerable catheter of claim 13, where the at least a first catheterlumen has a uniform consistent inner diameter along at least adistalmost terminal end length of the lumen, within which lumen lengthat least a first elongate wire is disposed and secured by the firstadhesive and the second adhesive.
 20. A method of forming the secureattachment of claim 19, said method comprising steps of: directing adistal lengthwise portion of the wire into a distal end of the catheterlumen where a distalmost terminal end of the wire is frayed or otherwiseat least partially disaggregated, and where said distalmost terminal endis within or immediately adjacent to the distalmost end terminal lengthof the catheter lumen; directing the first, more viscous, adhesivethrough a first hole into the catheter lumen in a manner that attachesand secures the wire within the catheter lumen, without blocking asecond hole; directing the second, less viscous, adhesive through thesecond hole in a manner that intersperses with and engages the frayed orotherwise at least partially disaggregated distalmost terminal end ofthe wire within the distalmost end terminal length of the catheterlumen.